Field of the Disclosure
The present disclosure generally relates to powering electronic devices, and more particularly, to a voltage regulator with switching and low dropout modes.
Description of the Related Art
Voltage regulators are used to provide power supplies for electronic devices. Different types of voltage regulators exhibit different voltage stability, noise, and regulation efficiency characteristics. Switching voltage regulators, such as buck mode voltage regulators, periodically couple an input voltage source to an energy storage element to generate an output voltage. Due to the periodic nature of the switching, the output voltage has an inherent ripple, making it less effective for noise sensitive devices, such as radios, especially during a receive mode of the radio.
In noise-sensitive applications, a low dropout (LDO) regulator may be used. A low dropout regulator couples an input voltage to an energy storage element using a transistor operating in a linear mode, thereby eliminating the ripple inherent in a switching voltage regulator.
Power consumption is another tradeoff associated with voltage regulators. Some electronic devices are powered by batteries, so a low efficiency voltage regulator will result in a reduced battery capacity. The relative efficiencies associated a switching voltage regulator versus an LDO regulator vary depending on the relationship between the input voltage and the output voltage. An LDO regulator may have improved noise characteristics, but lower efficiency than a switching regulator, resulting in increased current draw from the battery and lower battery capacity.
The use of the same reference symbols in different drawings indicates similar or identical items.